<?php

/*
	Question2Answer (c) Gideon Greenspan

	http://www.question2answer.org/

	
	File: qa-include/qa-app-captcha.php
	Version: See define()s at top of qa-include/qa-base.php
	Description: Wrapper functions and utilities for captcha modules


	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.
	
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	More about this license: http://www.question2answer.org/license.php
*/

if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
    header('Location: ../');
    exit;
}


function qa_captcha_available()
    /*
        Return whether a captcha module has been selected and it indicates that it is fully set up to go
    */
{
    $module = qa_load_module('captcha', qa_opt('captcha_module'));

    return isset($module) && ((!method_exists($module, 'allow_captcha')) || $module->allow_captcha());
}


function qa_captcha_reason_note($captchareason)
    /*
        Return an HTML string explaining $captchareason (from qa_user_captcha_reason()) to the user about why they are seeing a captcha
    */
{
    $notehtml = null;

    switch ($captchareason) {
        case 'login':
            $notehtml = qa_insert_login_links(qa_lang_html('misc/captcha_login_fix'));
            break;

        case 'confirm':
            $notehtml = qa_insert_login_links(qa_lang_html('misc/captcha_confirm_fix'));
            break;

        case 'approve':
            $notehtml = qa_lang_html('misc/captcha_approve_fix');
            break;
    }

    return $notehtml;
}


function qa_set_up_captcha_field(&$qa_content, &$fields, $errors, $note = null)
    /*
        Prepare $qa_content for showing a captcha, adding the element to $fields, given previous $errors, and a $note to display
    */
{
    if (qa_captcha_available()) {
        $captcha = qa_load_module('captcha', qa_opt('captcha_module'));

        $count = @++$qa_content['qa_captcha_count']; // work around fact that reCAPTCHA can only display per page

        if ($count > 1)
            $html = '[captcha placeholder]'; // single captcha will be moved about the page, to replace this
        else {
            $qa_content['script_var']['qa_captcha_in'] = 'qa_captcha_div_1';
            $html = $captcha->form_html($qa_content, @$errors['captcha']);
        }

        $fields['captcha'] = array(
            'type' => 'custom',
            'label' => qa_lang_html('misc/captcha_label'),
            'html' => '<div id="qa_captcha_div_' . $count . '">' . $html . '</div>',
            'error' => @array_key_exists('captcha', $errors) ? qa_lang_html('misc/captcha_error') : null,
            'note' => $note,
        );

        return "if (qa_captcha_in!='qa_captcha_div_" . $count . "') { document.getElementById('qa_captcha_div_" . $count . "').innerHTML=document.getElementById(qa_captcha_in).innerHTML; document.getElementById(qa_captcha_in).innerHTML=''; qa_captcha_in='qa_captcha_div_" . $count . "'; }";
    }

    return '';
}


function qa_captcha_validate_post(&$errors)
    /*
        Check if captcha is submitted correctly, and if not, set $errors['captcha'] to a descriptive string
    */
{
    if (qa_captcha_available()) {
        $captcha = qa_load_module('captcha', qa_opt('captcha_module'));

        if (!$captcha->validate_post($error)) {
            $errors['captcha'] = $error;
            return false;
        }
    }

    return true;
}


/*
	Omit PHP closing tag to help avoid accidental output
*/